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Diffstat (limited to '')
| -rw-r--r-- | src/activate/activate.c | 509 |
1 files changed, 509 insertions, 0 deletions
diff --git a/src/activate/activate.c b/src/activate/activate.c new file mode 100644 index 0000000..9a83bc7 --- /dev/null +++ b/src/activate/activate.c @@ -0,0 +1,509 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <getopt.h> +#include <sys/epoll.h> +#include <sys/prctl.h> +#include <sys/socket.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "sd-daemon.h" + +#include "alloc-util.h" +#include "escape.h" +#include "fd-util.h" +#include "log.h" +#include "macro.h" +#include "pretty-print.h" +#include "process-util.h" +#include "signal-util.h" +#include "socket-util.h" +#include "string-util.h" +#include "strv.h" +#include "terminal-util.h" + +static char** arg_listen = NULL; +static bool arg_accept = false; +static int arg_socket_type = SOCK_STREAM; +static char** arg_args = NULL; +static char** arg_setenv = NULL; +static char **arg_fdnames = NULL; +static bool arg_inetd = false; + +static int add_epoll(int epoll_fd, int fd) { + struct epoll_event ev = { + .events = EPOLLIN, + .data.fd = fd, + }; + + assert(epoll_fd >= 0); + assert(fd >= 0); + + if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) + return log_error_errno(errno, "Failed to add event on epoll fd:%d for fd:%d: %m", epoll_fd, fd); + + return 0; +} + +static int open_sockets(int *epoll_fd, bool accept) { + char **address; + int n, fd, r; + int count = 0; + + n = sd_listen_fds(true); + if (n < 0) + return log_error_errno(n, "Failed to read listening file descriptors from environment: %m"); + if (n > 0) { + log_info("Received %i descriptors via the environment.", n); + + for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) { + r = fd_cloexec(fd, arg_accept); + if (r < 0) + return r; + + count++; + } + } + + /* Close logging and all other descriptors */ + if (arg_listen) { + int except[3 + n]; + + for (fd = 0; fd < SD_LISTEN_FDS_START + n; fd++) + except[fd] = fd; + + log_close(); + close_all_fds(except, 3 + n); + } + + /** Note: we leak some fd's on error here. I doesn't matter + * much, since the program will exit immediately anyway, but + * would be a pain to fix. + */ + + STRV_FOREACH(address, arg_listen) { + fd = make_socket_fd(LOG_DEBUG, *address, arg_socket_type, (arg_accept*SOCK_CLOEXEC)); + if (fd < 0) { + log_open(); + return log_error_errno(fd, "Failed to open '%s': %m", *address); + } + + assert(fd == SD_LISTEN_FDS_START + count); + count++; + } + + if (arg_listen) + log_open(); + + *epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (*epoll_fd < 0) + return log_error_errno(errno, "Failed to create epoll object: %m"); + + for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + count; fd++) { + _cleanup_free_ char *name = NULL; + + getsockname_pretty(fd, &name); + log_info("Listening on %s as %i.", strna(name), fd); + + r = add_epoll(*epoll_fd, fd); + if (r < 0) + return r; + } + + return count; +} + +static int exec_process(const char* name, char **argv, char **env, int start_fd, size_t n_fds) { + + _cleanup_strv_free_ char **envp = NULL; + _cleanup_free_ char *joined = NULL; + size_t n_env = 0, length; + const char *tocopy; + char **s; + int r; + + if (arg_inetd && n_fds != 1) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "--inetd only supported for single file descriptors."); + + length = strv_length(arg_setenv); + + /* PATH, TERM, HOME, USER, LISTEN_FDS, LISTEN_PID, LISTEN_FDNAMES, NULL */ + envp = new0(char *, length + 8); + if (!envp) + return log_oom(); + + STRV_FOREACH(s, arg_setenv) { + + if (strchr(*s, '=')) { + char *k; + + k = strdup(*s); + if (!k) + return log_oom(); + + envp[n_env++] = k; + } else { + _cleanup_free_ char *p; + const char *n; + + p = strappend(*s, "="); + if (!p) + return log_oom(); + + n = strv_find_prefix(env, p); + if (!n) + continue; + + envp[n_env] = strdup(n); + if (!envp[n_env]) + return log_oom(); + + n_env++; + } + } + + FOREACH_STRING(tocopy, "TERM=", "PATH=", "USER=", "HOME=") { + const char *n; + + n = strv_find_prefix(env, tocopy); + if (!n) + continue; + + envp[n_env] = strdup(n); + if (!envp[n_env]) + return log_oom(); + + n_env++; + } + + if (arg_inetd) { + assert(n_fds == 1); + + r = rearrange_stdio(start_fd, start_fd, STDERR_FILENO); /* invalidates start_fd on success + error */ + if (r < 0) + return log_error_errno(r, "Failed to move fd to stdin+stdout: %m"); + + } else { + if (start_fd != SD_LISTEN_FDS_START) { + assert(n_fds == 1); + + if (dup2(start_fd, SD_LISTEN_FDS_START) < 0) + return log_error_errno(errno, "Failed to dup connection: %m"); + + safe_close(start_fd); + start_fd = SD_LISTEN_FDS_START; + } + + if (asprintf((char**)(envp + n_env++), "LISTEN_FDS=%zu", n_fds) < 0) + return log_oom(); + + if (asprintf((char**)(envp + n_env++), "LISTEN_PID=" PID_FMT, getpid_cached()) < 0) + return log_oom(); + + if (arg_fdnames) { + _cleanup_free_ char *names = NULL; + size_t len; + char *e; + + len = strv_length(arg_fdnames); + if (len == 1) { + size_t i; + + for (i = 1; i < n_fds; i++) { + r = strv_extend(&arg_fdnames, arg_fdnames[0]); + if (r < 0) + return log_error_errno(r, "Failed to extend strv: %m"); + } + } else if (len != n_fds) + log_warning("The number of fd names is different than number of fds: %zu vs %zu", len, n_fds); + + names = strv_join(arg_fdnames, ":"); + if (!names) + return log_oom(); + + e = strappend("LISTEN_FDNAMES=", names); + if (!e) + return log_oom(); + + envp[n_env++] = e; + } + } + + joined = strv_join(argv, " "); + if (!joined) + return log_oom(); + + log_info("Execing %s (%s)", name, joined); + execvpe(name, argv, envp); + + return log_error_errno(errno, "Failed to execp %s (%s): %m", name, joined); +} + +static int fork_and_exec_process(const char* child, char** argv, char **env, int fd) { + _cleanup_free_ char *joined = NULL; + pid_t child_pid; + int r; + + joined = strv_join(argv, " "); + if (!joined) + return log_oom(); + + r = safe_fork("(activate)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_RLIMIT_NOFILE_SAFE|FORK_LOG, &child_pid); + if (r < 0) + return r; + if (r == 0) { + /* In the child */ + exec_process(child, argv, env, fd, 1); + _exit(EXIT_FAILURE); + } + + log_info("Spawned %s (%s) as PID " PID_FMT ".", child, joined, child_pid); + return 0; +} + +static int do_accept(const char* name, char **argv, char **envp, int fd) { + _cleanup_free_ char *local = NULL, *peer = NULL; + _cleanup_close_ int fd_accepted = -1; + + fd_accepted = accept4(fd, NULL, NULL, 0); + if (fd_accepted < 0) + return log_error_errno(errno, "Failed to accept connection on fd:%d: %m", fd); + + getsockname_pretty(fd_accepted, &local); + getpeername_pretty(fd_accepted, true, &peer); + log_info("Connection from %s to %s", strna(peer), strna(local)); + + return fork_and_exec_process(name, argv, envp, fd_accepted); +} + +/* SIGCHLD handler. */ +static void sigchld_hdl(int sig) { + PROTECT_ERRNO; + + for (;;) { + siginfo_t si; + int r; + + si.si_pid = 0; + r = waitid(P_ALL, 0, &si, WEXITED|WNOHANG); + if (r < 0) { + if (errno != ECHILD) + log_error_errno(errno, "Failed to reap children: %m"); + return; + } + if (si.si_pid == 0) + return; + + log_info("Child %d died with code %d", si.si_pid, si.si_status); + } +} + +static int install_chld_handler(void) { + static const struct sigaction act = { + .sa_flags = SA_NOCLDSTOP|SA_RESTART, + .sa_handler = sigchld_hdl, + }; + + if (sigaction(SIGCHLD, &act, 0) < 0) + return log_error_errno(errno, "Failed to install SIGCHLD handler: %m"); + + return 0; +} + +static int help(void) { + _cleanup_free_ char *link = NULL; + int r; + + r = terminal_urlify_man("systemd-socket-activate", "1", &link); + if (r < 0) + return log_oom(); + + printf("%s [OPTIONS...]\n\n" + "Listen on sockets and launch child on connection.\n\n" + "Options:\n" + " -h --help Show this help and exit\n" + " --version Print version string and exit\n" + " -l --listen=ADDR Listen for raw connections at ADDR\n" + " -d --datagram Listen on datagram instead of stream socket\n" + " --seqpacket Listen on SOCK_SEQPACKET instead of stream socket\n" + " -a --accept Spawn separate child for each connection\n" + " -E --setenv=NAME[=VALUE] Pass an environment variable to children\n" + " --fdname=NAME[:NAME...] Specify names for file descriptors\n" + " --inetd Enable inetd file descriptor passing protocol\n" + "\nNote: file descriptors from sd_listen_fds() will be passed through.\n" + "\nSee the %s for details.\n" + , program_invocation_short_name + , link + ); + + return 0; +} + +static int parse_argv(int argc, char *argv[]) { + enum { + ARG_VERSION = 0x100, + ARG_FDNAME, + ARG_SEQPACKET, + ARG_INETD, + }; + + static const struct option options[] = { + { "help", no_argument, NULL, 'h' }, + { "version", no_argument, NULL, ARG_VERSION }, + { "datagram", no_argument, NULL, 'd' }, + { "seqpacket", no_argument, NULL, ARG_SEQPACKET }, + { "listen", required_argument, NULL, 'l' }, + { "accept", no_argument, NULL, 'a' }, + { "setenv", required_argument, NULL, 'E' }, + { "environment", required_argument, NULL, 'E' }, /* legacy alias */ + { "fdname", required_argument, NULL, ARG_FDNAME }, + { "inetd", no_argument, NULL, ARG_INETD }, + {} + }; + + int c, r; + + assert(argc >= 0); + assert(argv); + + while ((c = getopt_long(argc, argv, "+hl:aE:d", options, NULL)) >= 0) + switch(c) { + case 'h': + return help(); + + case ARG_VERSION: + return version(); + + case 'l': + r = strv_extend(&arg_listen, optarg); + if (r < 0) + return log_oom(); + + break; + + case 'd': + if (arg_socket_type == SOCK_SEQPACKET) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "--datagram may not be combined with --seqpacket."); + + arg_socket_type = SOCK_DGRAM; + break; + + case ARG_SEQPACKET: + if (arg_socket_type == SOCK_DGRAM) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "--seqpacket may not be combined with --datagram."); + + arg_socket_type = SOCK_SEQPACKET; + break; + + case 'a': + arg_accept = true; + break; + + case 'E': + r = strv_extend(&arg_setenv, optarg); + if (r < 0) + return log_oom(); + + break; + + case ARG_FDNAME: { + _cleanup_strv_free_ char **names; + char **s; + + names = strv_split(optarg, ":"); + if (!names) + return log_oom(); + + STRV_FOREACH(s, names) + if (!fdname_is_valid(*s)) { + _cleanup_free_ char *esc; + + esc = cescape(*s); + log_warning("File descriptor name \"%s\" is not valid.", esc); + } + + /* Empty optargs means one empty name */ + r = strv_extend_strv(&arg_fdnames, + strv_isempty(names) ? STRV_MAKE("") : names, + false); + if (r < 0) + return log_error_errno(r, "strv_extend_strv: %m"); + break; + } + + case ARG_INETD: + arg_inetd = true; + break; + + case '?': + return -EINVAL; + + default: + assert_not_reached("Unhandled option"); + } + + if (optind == argc) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "%s: command to execute is missing.", + program_invocation_short_name); + + if (arg_socket_type == SOCK_DGRAM && arg_accept) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), + "Datagram sockets do not accept connections. " + "The --datagram and --accept options may not be combined."); + + arg_args = argv + optind; + + return 1 /* work to do */; +} + +int main(int argc, char **argv, char **envp) { + int r, n; + int epoll_fd = -1; + + log_parse_environment(); + log_open(); + + r = parse_argv(argc, argv); + if (r <= 0) + return r == 0 ? EXIT_SUCCESS : EXIT_FAILURE; + + r = install_chld_handler(); + if (r < 0) + return EXIT_FAILURE; + + n = open_sockets(&epoll_fd, arg_accept); + if (n < 0) + return EXIT_FAILURE; + if (n == 0) { + log_error("No sockets to listen on specified or passed in."); + return EXIT_FAILURE; + } + + for (;;) { + struct epoll_event event; + + if (epoll_wait(epoll_fd, &event, 1, -1) < 0) { + if (errno == EINTR) + continue; + + log_error_errno(errno, "epoll_wait() failed: %m"); + return EXIT_FAILURE; + } + + log_info("Communication attempt on fd %i.", event.data.fd); + if (arg_accept) { + r = do_accept(argv[optind], argv + optind, envp, event.data.fd); + if (r < 0) + return EXIT_FAILURE; + } else + break; + } + + exec_process(argv[optind], argv + optind, envp, SD_LISTEN_FDS_START, (size_t) n); + + return EXIT_SUCCESS; +} |